From 3b71be3bf0942c5825370ed579d66f01579c94d9 Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Thu, 30 May 2019 05:33:59 -0400
Subject: [PATCH] fix #537

---
 irc/channelmanager.go | 33 ++++++++++++++++++++++-----------
 irc/config.go         |  3 ++-
 oragono.yaml          |  4 ++++
 3 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/irc/channelmanager.go b/irc/channelmanager.go
index ad07d1c6..8ceb390b 100644
--- a/irc/channelmanager.go
+++ b/irc/channelmanager.go
@@ -65,19 +65,30 @@ func (cm *ChannelManager) Join(client *Client, name string, key string, isSajoin
 		return errNoSuchChannel
 	}
 
-	cm.Lock()
-	entry := cm.chans[casefoldedName]
-	if entry == nil {
-		registered := cm.registeredChannels[casefoldedName]
-		entry = &channelManagerEntry{
-			channel:      NewChannel(server, name, registered),
-			pendingJoins: 0,
+	channel := func() *Channel {
+		cm.Lock()
+		defer cm.Unlock()
+
+		entry := cm.chans[casefoldedName]
+		if entry == nil {
+			registered := cm.registeredChannels[casefoldedName]
+			// enforce OpOnlyCreation
+			if !registered && server.Config().Channels.OpOnlyCreation && !client.HasRoleCapabs("chanreg") {
+				return nil
+			}
+			entry = &channelManagerEntry{
+				channel:      NewChannel(server, name, registered),
+				pendingJoins: 0,
+			}
+			cm.chans[casefoldedName] = entry
 		}
-		cm.chans[casefoldedName] = entry
+		entry.pendingJoins += 1
+		return entry.channel
+	}()
+
+	if channel == nil {
+		return errNoSuchChannel
 	}
-	entry.pendingJoins += 1
-	channel := entry.channel
-	cm.Unlock()
 
 	channel.EnsureLoaded()
 	channel.Join(client, key, isSajoin, rb)
diff --git a/irc/config.go b/irc/config.go
index a3ed6267..8897636d 100644
--- a/irc/config.go
+++ b/irc/config.go
@@ -320,7 +320,8 @@ type Config struct {
 	Channels struct {
 		DefaultModes         *string `yaml:"default-modes"`
 		defaultModes         modes.Modes
-		MaxChannelsPerClient int `yaml:"max-channels-per-client"`
+		MaxChannelsPerClient int  `yaml:"max-channels-per-client"`
+		OpOnlyCreation       bool `yaml:"operator-only-creation"`
 		Registration         ChannelRegistrationConfig
 	}
 
diff --git a/oragono.yaml b/oragono.yaml
index 35754dea..51415e84 100644
--- a/oragono.yaml
+++ b/oragono.yaml
@@ -368,6 +368,10 @@ channels:
     # how many channels can a client be in at once?
     max-channels-per-client: 100
 
+    # if this is true, new channels can only be created by operators with the
+    # `chanreg` operator capability
+    operator-only-creation: false
+
     # channel registration - requires an account
     registration:
         # can users register new channels?